Supply rail for electrical distribution systems

ABSTRACT

A supply rail for use in electrical distribution systems having a pair of hollow compartments separated by a center bar. Each compartment is provided with a slit opening for receiving a contact device. Each compartment is provided with a current bar carried on an insulated carrier body which is located on a sidewall of each hollow compartment. The carrier body abuts against abutments on said sidewall to produce an airgap between the carrier body and the sidewall in each compartment. The airgap is available to receive at the ends of the supply rail projections of insulating material to provide a connection means between sections of a supply rail or an end cap.

United States Patent Inventor Max Laser Lidingo, Sweden Appl. N 0. 797,524 Filed Feb. 7, 1969 Patented Mar. 9, 1971 Assignee U. S. Philips Corporation New York, N.Y. Priority Feb. 9, 1968 Sweden 1762/68 SUPPLY RAIL FOR ELECTRICAL DISTRIBUTION SYSTEMS 4. Claims, 3 Drawing Figs.

US. Cl 339/14, 339/21 Int. Cl. H01r 41/00 Field of Search V g 9 2s 4 hi i 16 s A j A 20 22 L t 18 Primary Examiner-Marvin A. Champion Assistant ExaminerPatrick A. Clifford Attorney- Frank R. Trifari ABSTRACT: A supply rail for use in electrical distribution systems having a pair of hollow compartments separated by a center bar. Each compartment is provided with a slit opening for receiving a contact device. Each compartment'is provided with a current bar carried on an insulated carrier body which I is located on a sidewall of each hollow compartment. The carrier body abuts against abutments on said sidewall to produce an airgap between the carrier body and the sidewall in each compartment. The airgap is available to receive at the ends of the supply rail projections of insulating material to provide a connection means between sections of a supply rail or an end cap. 1

SUPPLY RAIL FOR ELEC RICAL DISTRIBUTION SYSTEMS The invention refers to a supply rail for use in distribution systems for electric current, which rail has the shape of a hollow profile with at least one current bar mounted on an insulating carrier body extending along one sidewall of the profile. The supply rail is adapted to cooperate with a contact device, which is introduced into a slit-shaped opening in the profile and which device has contact means which are shaped such that they at the introduction of the contact device onto the rail will come in touch with the current bar.

Such distribution systems can be used for illumination and small apparatuses in exhibition and industry locals and in cases where it is required to have an illumination or electrical apparatuses which are to be adapted to the actual need. The supply rail can be mounted in the ceiling, on the walls adjacent to the floor and possible in the floor. Armature and cables can be connected directly to the contact device, which is introduced at a suitable place in the system. Current supply to the current bars can be efiected by means of special connection devices at one end of each bar or alternatively through the same type of contact devices which are used for current tapping.

The supply rails are manufactured in sections and the profile is made of metal, for example, aluminum, so as to achieve sufficient rigidity. A problem which then arises is to produce sufficient insulation between the current bar and the metallic profile. Along the section the current bar will be protected relative to the metallic envelope by the insulating carrier body, on which the bar is mounted, but at the ends of each section it will be exposed against the profile. Without special insulation means at the ends of the sections it should consequently be necessary to have the current bar situated at such a distance from the metallic profile, which corresponds to the minimum creep distance for the actual voltage. This will, however, involve poor utilization of the space and counteracts the requirements on small dimensions of the rail. If on the other hand some sort of insulation is arranged at the ends of each section it will be necessary at the mounting of the rails to use given section lengths only. It must, however, be regarded as a primary requirement that it shall be possible at the joining of a number of sections to a complete rail, to cut some sections to required lengths for adapting the rail system to given dimensions of the local.

It is an object of the invention, to provide a supply rail which can be manufactured with minimum dimensions while fulfilling given safety requirements and which rail can be cut to required lengths and be immediately ready for use in joining or as an end termination after the cutting. The characteristic of the invention consists in that between the insulating carrier body, on which the current bar is mounted, and the sidewall of the metallic profile along which the carrier body extends, there is an airgap and that at joining or end termination an insulating body projecting from the part to be joined is introduced into the said gap. The creep distance can hereby be increased to any value by varying the length of the said insulating body in spite of a very small geometrical distance between the current bar and the metallic profile.

The invention is illustrated in the accompanying drawing, in which:

FIG. 1 shows a sectional view through a supply rail shaped in accordance with the invention;

FIG. 2 shows a partial sectional view of the rail according to FIG. I taken along line AA in FIG. 1 and with a joining piece connected to the rail, and

FIG. 3 is an end view of a cover lid for the end of the supply rail.

The shown supply rail consists of a substantially rectangular hollow profile l, which at opposite sidewalls has projecting portions 2, 3, where insulating carrier bodies 4,5 for current bars 6, 7 are introduced. A center bar 8 divides the inner of the profile in two portions, so that the current bars are situated in separate room 9, 10. Through the center bar there extend holes 11 adapted for screws, by means of which the rail can be fixed to a base. Slit-shaped openings 12, 13 are formed on each side of the center bar between the said bar and portions 14, 15 of the profile, which serve as holder for the insulating carrier bodies 4, 5. Elastic protecting strips l6, 17 of insulat ing material protect the current bars 6, 7 against unintentional contact. Protecting strips 18, 19 made integral with the first strips are further arranged for covering the openings l2, 13.

The supply rail is adapted tocooperate with a contact device as described in copending U.S. application Ser. No. 797,567, filed Feb. 7, 1969 provided with contact springs which are introduced into the openings l2, l3 and which device is fixed by means of springs engaging recesses 20, 21 in the center bar. The contact springs are provided with hookshaped end portions, which are introduced between the protecting strips 16, 17 an the carrier bodies 4, 5 and brought into contact with the current bars 6, 7. In one of the recesses in the center bar there is furthermore a grounded current bar 22.

The profile 1 can be made of aluminum and manufactured by extrusion. The protecting strips 16l9 consists suitably of durable soft plastic material and the insulating carrier body 4, 5 can consist of thermo setting plastic material or ceramic material.

The insulating carrier bodies 4, 5 for the current bars 6, 7 are according to the invention mounted at a distance from the adjacent sidewalls 2, 3 of the metallic profile, so that airgaps 24, 25 are formed between the insulating bodies and the metallic profile. The airgaps are maintained along the whole length of the rail in thatthe carrier bodies 4, 5 bear against continuous supports 26, 27 and 28, 29 respectively of the profile, which supports serve as distance means. When joining or end termination of the individual rail sections, insulation bodies are introduced into the airgaps 24, 25, which bodies extend a distance into the airgap and thereby will interrupt the direct current path from the current bar to the metallic profile. This is illustrated in FIG. 2, which shows a partial sectional view of the supply rail taken along line AA in FIG. 1 after introducing a joining piece on the rail. The portion of the supply rail in FIG. 2 is at the bottom part of FIG. 1 and the joining piece which is generally designated 30, is shown introduced from above. The joining piece is shaped in the same way as the rail itself and consists of a metallic profile 31 with insulating carrier body 32 for a current bar 33, and a protecting strip. 34. At its end the joining piece has a projecting tongue 35, which is made integral with the carrier body 32. The tongue 35 is dimensioned in conformance with the airgap 24 in the supply rail and at the mounting of the piece upon the rail introduced intothe said gap, as shown in FIG. 2. The insulating tongue can suitably be of the same width as the airgap, so that it fills the whole gap. A similar projecting tongue, which fits into the airgap 25, is arranged at the opposite side of the joining piece. If the section shown in FIG. 1 is regarded as the end surface of the rail, which has the same shape as the section, it is evident from the figure that the creep distance" h in FIG. 1, which is partly formed by theairgap by the introduction of the insulating tongue has been changed to an appreciably longer creep distance H show by dotted line in FIG. 2. The creep distance H can be made of any length by varying the length of the insulating tongue projecting from the joining piece. In the shown example there is another creep distance h which, however, without changing the dimension of the rail can be increased to any value by varying the position of the current bar in the profile. At the opposite end of the joining piece there are two similar projecting insulating tongues, which are introduced into the next section of the rail.

In a practical example the distance between the current bar and the metallic profile is 3 mm, whereof 1.5 mm is formed by the airgap h,. This is not sufficient for normal voltages according to present security requirements if the joint surface had the shape as shown in FIG. 1, but by producing an extended creep distance H according to FIG. 2 the safety requirements are fulfilled also with this short distance between current bar and metallic profile.

At joining two sections furthermore special contact means must be arranged for producing electric connection between the current bars of the supply rail and the joining piece.

Connection devices for feeding supply voltage to the current bars have ends which are shaped in the same way as the shown joining piece. For producing end termination of a rail a lid 36 is used, which covers the whole end surface of the profile and which is provided with projecting insulating tongues 37, which at the mounting of the lid are introduced into the airgaps 24, 25.

Iclaim:

l. A supply rail for use in electric current distribution systems adapted for cooperation with a contact device having contact means, said supply rail comprising a hollow metal profile, a center bar extending the length of said profile dividing said profile into two adjacent hollow compartments, a slitshaped opening in a front wall of each of said compartments for receiving said contact device, an insulating carrier body mounted within each of said hollow compartments and extending along a sidewall of said profile, abutment means located on each of said sidewalls so that said carrier body engages said abutment means spacing said carrier body from each of said sidewalls of an airgap thereby being established between said carrier body and the sidewall along which said carrier body is located, said gap extending the full length of each of said sidewalls and intended to receive insulating bodies at the end of the supply rail and an additional current bar for connection to ground mounted on said center bar,

2. A supply rail for use in electric current distribution systems according to claim 1 wherein a cover lid is mounted on one of the ends of said supply rail, said lid having projecting insulating bodies located within said airgaps.

3. A supply rail for use in electric current distribution systems according to claim 2 wherein another supply rail having projecting insulating bodies is connected with the other end of said supply rail, said projecting insulating bodies of said other supply rail cooperating with the said airgaps of the said supply rail, said projecting insulating bodies overlapping the connection point between said supply rails.

4. A supply rail for use in electric current distribution systems according to claim 1 further comprising a current bar carried by each of said carrier bodies. 

1. A supply rail for use in electric current distribution systems adapted for cooperation with a contact device having contact means, said supply rail comprising a hollow metal profile, a center bar extending the length of said profile dividing said profile into two adjacent hollow compartments, a slit-shaped opening in a front wall of each of said compartments for receiving said contact device, an insulating carrier body mounted within each of said hollow compartments and extending along a sidewall of said profile, abutment means located on each of said sidewalls so that said carrier body engages said abutment means spacing said carrier body from each of said sidewalls of an airgap thereby being established between said carrier body and the sidewall along which said carrier body is located, said gap extending the full length of each of said sidewalls and intended to receive insulating bodies at the end of the supply rail and an additional current bar for connection to ground mounted on said center bar,
 2. A supply rail for use in electric current distribution systems according to claim 1 wherein a cover lid is mounted on one of the ends of said supply rail, said lid having projecting insulating bodies located within said airgaps.
 3. A supply rail for use in electric current distribution systems according to claim 2 wherein another supply rail having projecting insulating bodies is connected with the other end of said supply rail, said projecting insulating bodies of said other supply rail cooperating with the said airgaps of the said supply rail, said projecting insulating bodies overlapping the connection point beTween said supply rails.
 4. A supply rail for use in electric current distribution systems according to claim 1 further comprising a current bar carried by each of said carrier bodies. 